Probiotics and Antimicrobial Proteins最新文献

The significance of the intestinal microbiota in overall health has gained increasing recognition. Probiotic supplementation promotes intestinal microbial homeostasis. As a key component of probiotics, lactic acid bacteria (LAB) are widely utilized in the prevention and management of various diseases owing to their well-established safety profile and remarkable immunomodulatory properties. Their regulatory effect on myeloid cells, particularly macrophages, is critically important. This article systematically reviews the substantial impacts of LAB on macrophages, including effects on macrophage quantity, polarization, autophagy, apoptosis, metabolism, trained immunity, and so on, which contribute to the control of disease progression. The regulation of macrophages by LAB exhibits characteristics such as strain-specificity, dose dependence, and correlation with administration routes, and may mediate systemic effects via the gut-X axis. Furthermore, LAB have demonstrated therapeutic potential in treating macrophage-associated diseases, such as obesity and impaired wound healing. Finally, this review discusses development suggestions for the combined application of LAB and future development directions in this field, including screening and combined application of strains, exploring and utilizing the mechanism of transgenerational effect, aiming to enhance the application of LAB in antibiotic therapy and the development of human and animal health industries.

This study investigated the production of low-molecular-weight peptides (< 3 kDa) from milk proteins by endemic lactic acid bacteria strains and examined the effects of strain type, fermentation, and storage time on functional peptide formation to identify promising bioactive peptides and their producer strains for targeted functional dairy applications. To achieve this, < 3 kDa peptide fractions obtained from fermented milk with various LAB strains were characterized using LC-QTOF-MS. The highest peptides numbers were identified in samples fermented with Lactobacillus (Lb.) helveticus. β-casein-derived peptides predominated due to its high abundance in milk and flexible structure, which makes it more susceptible to proteolysis by LAB enzymes. This facilitates extensive peptide release during fermentation, and many of these fragments possess known antimicrobial activities, explaining their strong contribution to antibacterial potential. In vitro antibacterial activities were also assessed, and peptide sequences were scored for antibacterial potential using a Random Forest model. Random Forest analysis indicated that β-casein derived peptides were the main contributors to antibacterial potential. Serum albumin was hydrolyzed to a greater extent compared to other whey proteins. <3 kDa peptide fractions demonstrated inhibitory activity only against the Gram-negative bacteria Salmonella (S.) Typhimurium and Escherichia (E.) coli. The anticancer activities of the peptide fractions were evaluated against colorectal (HT-29), hepatocellular (Hep-G2), and breast (MCF-7) cancer cell lines, along with their immunomodulatory effects on RAW 264.7 macrophages. Anticancer activity was observed to be dose-dependent across all tested cell lines, with the most pronounced inhibitory effect generally detected at 50 µg/mL (p < 0.05). Peptide fractions derived from L. paraplantarum showed the strongest inhibitory effects against all tested cancer cell lines. Although no significant increase was observed in IL-12 and IL-6 levels, peptide fractions from L. paraplantarum and Lb. helveticus 11B2, enhanced TNF-α production in macrophages, indicating a controlled activation of macrophage-mediated innate immune responses that may contribute to antitumor immunity. This study demonstrates a clear strain-dependent divergence in peptide bioactivity, with L. paraplantarum NCCB 100,523 being associated with stronger anticancer and immunomodulatory effects, while Lb. helveticus 12B1 and Lb. helveticus 11B2 were linked to enhanced antibacterial activity, indicating their practical relevance for the targeted design of bioactive peptides and the development of functional foods with specific biological functions.

With the trend shifting towards reducing antibiotic usage, the utilization of lactobacilli as a probiotic is emerging as an alternative, effective method for mitigating Salmonella infection in the poultry industry. Here, we investigated the antimicrobial activity of cell-free culture supernatants (CFCS) of three lactobacilli (Lactobacillus (Lact.) johnsonii, Lact. reuteri and Lact. crispatus) isolated from caecal microbiota from mature, healthy broiler chickens, against five Salmonella enterica serovars (Salm. Typhimurium 4/74, Salm. Enteritidis P125109, Salm. Enteritidis AviPro^®, Salm. Gallinarum 9 and Salm. Gallinarum 287/91). Lactobacilli CFCS demonstrated potent bactericidal activity against all Salmonella serovars although the degree of inhibition varied amongst the three strains, where MIC ranged from 8.98 to 18.58 mg/mL, and MBC from 12.62 to 25.54 mg/mL. In support, co-culture assays confirmed all serovars as being completely inhibited by lactobacilli CFCS within 3-6 h. In agar well diffusion assays, Lact. crispatus demonstrated highest inhibitory activity, with Salm. Gallinarum showed highest susceptibility. Lactobacilli CFCS significantly suppressed Salmonella invasion of caecal enterocytes and proinflammatory cytokine release from macrophages. Molecular characterisation of inhibitory moieties within lactobacilli CFCS established they were ≤ 3 kDa, pH dependant, heat tolerant and resistant to proteases. Head-space solid-phase microextraction-gas chromatography/mass spectrometry identified volatile organic short- and medium-chain fatty acids, aldehydes, alcohols, ketones and pyrazines as candidate anti-Salmonella post-biotics generated by lactobacilli. In conclusion, lactobacilli isolated from the caecal microbiota of healthy broiler chickens exhibit excellent potential as probiotic candidates to control salmonellosis in poultry and warrant testing in flock intervention studies.

Gut microbiota resilience, the capacity of intestinal microbial communities to resist, adapt, and recover from perturbations has emerged as a critical determinant of human health and longevity. Environmental stressors such as antibiotics, pollutants, poor diet, infections, and psychosocial stress challenge this resilience, often leading to dysbiosis (a sustained disruption of microbial community structure and/or function), impaired metabolism, chronic inflammation, and increased disease susceptibility across the lifespan. While dysbiosis has been extensively studied, the resilience dimension remains underexplored, particularly in the context of cumulative and repeated stress exposures. This narrative review explores microbial resilience, identifying environmental disruptors, and their manifestation at life stages, highlighting its hidden yet crucial role in optimizing lifespan. We critically evaluate the consequences of reduced resilience for chronic disease, frailty, and therapeutic response, while emphasizing the protective roles of diversity, functional redundancy, and host-microbe feedback loops. Translational strategies including dietary modulation, microbial therapeutics, behavioral interventions, and precision tools such as multi-omics and biosensors, are assessed for their potential to strengthen resilience and promote healthy aging. By reframing gut microbiota resilience as both a biological property and a public health target, this work advances a novel perspective: that fostering resilience may mitigate environmental insults, personalize interventions, and extend healthspan.